Method and apparatus for manufacturing paint roller and product produced thereby

ABSTRACT

The invention consists of applying thermoplastic adhesive in a molten state in the area where a strip of pile fabric is wound onto a plastic tube which is mounted over a rotating roller. The molten thermoplastic adhesive is applied by a nozzle connected to a reservoir where the thermoplastic adhesive is heated After application, the adhesive, the strip of pile fabric and the plastic tube are joined together, forming a structurally integral paint roller body.

This application is a continuation of U.S. patent application Ser. No.07/489,398, filed Mar. 6, 1990, now abandoned, which application claimsthe benefit of the filing date pursuant to 35 U.S.C. 119 of the Spanishapplication Ser. No. 8900821 filed Mar. 7, 1989.

BACKGROUND OF THE INVENTION

Currently in the manufacture of paint rollers, strips of pile fabric areused which are wound around a plastic or cardboard tube or core. Morespecifically, among the devices currently employed is a type of machineillustrated in Spanish Utility Model No. 293.980, which machine includesof a rotating cylinder over which the plastic or cardboard tube ismounted, and onto which a strip of pile fabric is applied through aguide oriented obliquely and situated on and carried by a carriage whichis mounted in fixed fashion over a sliding apparatus. The bonding of theplastic tube and strip of pile fabric is accomplished either by theapplication of adhesive material or by the use of a plastic tube which,when heated by means of gas burners, bonds to the strip of pile fabric,thereby forming a single body.

In the first case, i.e., where conventional adhesive is used as themeans of bonding between the tube and strip of pile fabric, themanufacture of paint rollers presents significant problems, allresulting from the difficulty of applying the adhesive uniformly, plusthe fact that very specific adhesives must be used to produce the bondbetween the tube and the strip of pile fabric so that, when the rollersare used, these adhesives do not separate due to the solvents containedin the paint and in the fluids used to clean the roller.

These problems considerably increase the cost of manufacturing paintrollers because the cost of the adhesives and the time needed for theadhesives to harden.

The second system mentioned above, though a significant advance in theart over what had been earlier used, does present certain problems, allresulting from the increased safety costs required by installations thatuse gas. Further, the heating of the plastic tube can produceundesirable products of combustion and high noise, both effects beingpotentially harmful for the operations and expensive to eliminate; allof this therefore has the result of raising the cost of the finalproduct.

SUMMARY OF THE INVENTION

The object of the present invention is a procedure for manufacturingpaint rollers of the type in which a strip of pile fabric is woundhelically over a plastic tube, with the interposition of a thermoplasticadhesive in a molten state, with the result that the strip of pilefabric and the plastic tube form a single paint roller body.

Specifically, the thermoplastic adhesive, which may be polypropylene, ina molten state is applied onto the plastic tube in the area adjacent tothe area of the winding of the strip through a nozzle connected to areservoir where the thermoplastic adhesive is heated, which nozzle ismounted on the carriage on which the pile fabric strip applicator isalso located.

Another object of the present invention is the provision of a paintroller which is structurally integral as a result of the bonding of thethermoplastic adhesive with the strip of the pile fabric and the plastictube.

DESCRIPTION OF THE DRAWING

The invention is illustrated more or less diagrammatically in theaccompanying drawing wherein,

FIG. 1 is a plan view of the plastic tube mounted over the rotatingroller and the strip of pile fabric being wound helically and themovable carriage on which are situated the applicator of the pile fabricstrip and the nozzle for applying the thermoplastic adhesive in a moltenstate.

FIG. 2 is a plan view of the plastic tube mounted on a rotating rollerand movable longitudinally by means of a drive unit, and wherein thestrip of pile fabric is wound helically, and the fixed carriage on whichthe applicator of the thermoplastic adhesive in a molten state islocated.

FIG. 3 is a sectional view of either of the above Figures showing asection of the roller already constructed, wherein the strip of pilefabric, the thermoplastic adhesive and the plastic tube form a singlebody.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The procedure for manufacturing paint rollers that is the object of thepresent invention includes the use of a machine that has a rotatingroller 1 on which the plastic tube 2 is mounted. The machine also has acarriage 3 which, in FIG. 1, is movable parallel to the longitudinalaxis of the rotating roller. The carriage 3 includes a feed mechanismfor pile fabric strip 4 to be helically wound around the plastic tube 2.

The procedure consists of a first operative phase in which the plastictube 2 is mounted over the rotating roller 1 and a second operativephase in which the strip of pile fabric 4 is wound helically over theplastic tube 2 through the applicator located on the movable carriage 3.

The fundamental characteristics of the present procedure for themanufacture of paint rollers consists of applying onto the area of theplastic tube 2 where the strip 4 will be closely wound a thermoplasticadhesive in a molten state. It will be understood that the specificthermoplastic adhesive material applied to the junction region betweenthe tube and fabric is not critical to the invention. It need only becompatible with the plastic tube selected, and the pile fabric. It isapplied by the outlet mouth of the nozzle 5 mounted over the movablecarriage 3, which nozzle 5 is connected to a reservoir where thethermoplastic adhesive is heated.

In the embodiment of FIG. 2, the plastic tube 2 is mounted over arotating roller 7. The plastic tube may be moved longitudinally by adrive unit 8, while the carriage 3 and the rotating roller 7 remainsaxially fixed.

In both cases, the system includes a cutter 6 which produces the rollerunits in a condition ready for the subsequent assembly of the handle,axis and cap. In the embodiment of FIG. 1, the cutter 6 does not movehorizontally when cutting In the embodiment of FIG. 2 it will beunderstood that the cutter 6 will be arranged to move in synchronismwith the horizontal movement of the tube 2 when cutting.

The system produces a paint roller comprised of a structurally integralelement due to the bonding produced between the plastic tube 2 and thestrip of pile fabric 4, together with the interposition of thecompatible thermoplastic adhesive which has been heated to a temperaturecapable of forming a strong bond. The exact temperature will of coursevary slightly from material to material and other factors unique to aspecific operation as will be readily apparent to one skilled in theart.

With this procedure, the high expenditures that must be incurred for thesafety measures that are currently required when gas installations areused in the manufacture of this type of roller are avoided; also, thedisagreeable products of combustion and elevated noise level which canbe potentially harmful for operation are eliminated since thethermoplastic adhesive is heated in an independent reservoir that may belocated at a considerable distance from the site where the rollers aremanufactured.

Although a preferred embodiment of the invention has been illustratedand described it will at once be apparent to those skilled in the artthat modifications and improvements may be made within the scope of theinvention. Accordingly it is intended that the scope of the inventionnot be limited by the foregoing exemplary description, but only by thehereafter appended claims when interpreted in view of the relevant priorart.

I claim:
 1. In a continuous method of producing a structurallyintegrated paint roller, the steps of,providing a thermoplastic paintroller core compatible with polypropylene, presenting a thermoplasticfabric in strip form to the paint roller core, said fabric having abacking compatible with polypropylene, providing a supply ofpolypropylene which is compatible with both the paint roller core andthe strip fabric and which is capable of functioning, upon applicationof heat, as an adhesive, heating said supply of polypropylene to atemperature at which it becomes a liquid adhesive, applying said hotliquid polypropylene to the rotating core immediately prior to theplacement of the strip on the core in an amount sufficient to securelybond the strip to the core so as to yield a structurally integralproduct, and wrapping said fabric while said polypropylene is in hotmolten adhesive condition about the core and said fabric and core arerotating with respect to each other.